Signage is a critical aspect of communication in our organized society. Signage used in the public-transit industry is a well known example of the critical usage of such communication. A plurality of signs may often be positioned in and/or around a bus, train, or other mode of transit to display information to passengers, potential passengers, and/or other observers. A destination sign or destination indicator is a sign mounted on the front or side interior or exterior of a public transport vehicle, such as a bus, tram, streetcar or light rail vehicle. A destination sign displays the vehicle's route number and/or destination, or the route's number and name when a transit system utilizes route names. The main destination sign is usually mounted on the front of the vehicle in a location above (or at the top of) the windshield. This main sign is often called the headsign. For example, as shown in FIG. 1, a bus 10 may display route or destination information on a headsign 12 disposed on the outside thereof. The headsign information can easily be observed and read by a passer by. Rider decisions are often based on such signs. The destination information or destination message may include the name of the route that the particular bus is servicing so that potential passengers waiting at a bus stop will know which bus to board. Depending on the type of the sign, it may also display intermediate destination points on the current route, especially if the route is particularly long and its final terminus, by itself, is not very helpful in determining where the vehicle is going. Similarly, destination signs are often disposed inside a bus or train to provide passengers inside the bus or train with information such as the name of the next or present stop on the bus or train route. An interior destination sign 14 may be mounted on an interior side or interior forward portion ceiling, or wall of a bus or train. FIG. 2 depicts a ceiling mount destination sign 16 and wall mount destination sign 18 found in the interior of a mass-transit light rail vehicle.
Several different types of technology have been used for destination and other signs on a bus, train, or rail car. Such different types of technology range from simple rigid placards held in place by a frame or clips, to rollsigns, to various types of computerized or electronically controlled signs, such as flip-disc, LCD or LED style displays. For many decades, the most common type of multiple-option destination sign was the rollsign, or indicator blind. These consist of a roll with pre-printed route numbers/letters and destinations (or route names), which is turned by the vehicle operator at, for example, the end of the route when reversing direction, either by a hand crank or by holding a switch if the rollsign mechanism is motorized.
One of the first electronic signs widely used for public-transit signs were flip-disc, or “flip-dot” displays 20, such as the one shown in FIG. 3. These flip-dot displays are limited in their display capabilities to a dot matrix display. In general, dot matrix displays are suitable for displaying information on machines, clocks, railway departure indicators and many other devices requiring a simple display of limited resolution. Such dot-matrix displays consist of a matrix of mechanical indicators arranged in a rectangular configuration (other shapes are also popular, although not common) such that by switching on or off selected lights or flipping selected light or dark colored dots, text or low resolution graphics is displayed. More recently, LED and LCD panels have replaced the mechanical indicators of flip-dot displays. The recent LED and LCD displays consist of a plurality of discrete lights organized to be generally limited to dot-matrix display formats. The use of dot-matrix displays in public transportation has been widely adopted because of various regulatory requirements such as, for example, the regulatory requirements required by the American Disabilities Act (ADA) that specify design criteria for transit-vehicle destination signs, including maximum and minimum character height-to-width ratio and contrast levels between lettering illumination and color and a black background. The various regulatory requirements were enacted to ensure that destination signs on transit vehicles are sufficiently readable to visually impaired persons.
Dot-matrix destination signs, as discussed above, still have limited resolution even though newer LCD or LED technology has been incorporated into their design. Thus, what is needed is a light-weight electronic signage system that meets or exceeds the regulatory requirements for public transportation destination signs, by providing improved high visibility and readability along with higher graphic image resolution that overcomes the limitations of former dot-matrix destination display designs.